Exercise equipment has been designed using a variety of resistance mechanisms. One known exercise resistance mechanism includes a flywheel that rotates against frictional resistance created by contact between a drag strap and an outer cylindrical surface on the flywheel. This particular resistance mechanism has been incorporated into cross-country skiing exercise machines, such as those disclosed in U.S. Pat. Nos. 4,023,795 and 4,728,102, rowing exercise machines, such as that disclosed in U.S. Pat. No. 5,072,929, and other types of exercise apparatus, such as the combination exercise apparatus designated as 100 in FIG. 5 herein.
In general, the above-identified flywheel mechanism provides resistance that is highly desirable for the intended purpose. However, one disadvantage of this prior art flywheel mechanism is that the resistance to exercise does not always remain consistent during extended operation. In extreme cases, the resistance level increases or "creeps" by as much as fifty percent (from twenty (20) pounds to thirty (30) pounds) during only twenty minutes of continuous operation. Even in more moderate cases, the "creep" or load increase is perceptible to the user of the exercise apparatus, and any perceived deviation is obviously undesirable.
Numerous experiments and tests have been conducted in an effort to identify the cause of and solve this problem with "creeping" resistance levels but without success prior to the present invention. For example, Prior Art flywheel resistance mechanisms have used sand cast grey iron flywheels and die cast zinc flywheels alternatively with nylon straps and woven polyester straps, but none of these combinations proved to be the solution to the "creeping" resistance problem. Additional attempts to eliminate "creeping" resistance have involved coating the outer cylindrical surface of the flywheel with a lubricant or plating the outer cylindrical surface with materials such as chrome or porcelain but without success. At one point, plating the surface with black zinc was thought to be the solution, but further testing proved otherwise. Since none of the prior art combinations have effectively eliminated the inconsistent resistance problem, the need remains for an improvement to this type of resistance mechanism so that the frictional resistance remains essentially constant during extended operation.